When more than one compartment of a compartmentalized truck or trailer is to be conditioned, a host refrigeration unit is conventionally mounted on a front wall of the truck or trailer, adjacent to a front compartment, and a remote evaporator unit is mounted in a rear compartment. The host refrigeration unit includes a condenser, and an evaporator for conditioning the air of a cargo space in the front compartment. The remote refrigeration unit includes an evaporator for conditioning the air of a cargo space in the rear compartment. U.S. Pat. Nos. 4,685,306; 4,706,468; 4,711,095; 4,712,383; 4,896,512; 4,912,940 and 4,932,219, which are assigned to the same assignee as the present application, all disclose compartmentalized transport refrigeration systems of the type described above.
The host-remote refrigeration arrangement adequately controls the temperatures of the cargo spaces in the associated compartments, but there are several disadvantages. For example, the host-remote refrigeration arrangement is costly to manufacture because it includes multiple components. The host-remote arrangement is difficult and time consuming to install because of the separate mounting of the host and remote refrigeration units, the separate electrical harness required for the remote unit, and the long hot gas, liquid and suction lines which must be run between the host and remote refrigeration units. The separate mounting and separate connections involved requires that the whole refrigeration system be evacuated and charged with refrigerant after installation on a truck or trailer. Since the system is not factory assembled and factory tested, in general it would be less reliable, as factory quality control procedures would not be applicable. The refrigerant hoses and electrical harness which connect the remote unit with the host unit are susceptible to damage and must be protected by special covers or special channels. Maintenance costs associated with such systems are relatively high because of added inspection for damage and refrigeration leaks, and associated repair costs when damage and/or refrigeration leaks are detected. A walk-in side door is normally provided on the truck or trailer for accessing the front compartment. A side door on a truck or trailer usually requires that products in the front compartment be loaded and unloaded by hand. Thus, it would be desirable, and it is an object of the present invention, to have a compartmentalized truck or trailer and associated transport refrigeration system for refrigerating the compartments which overcomes the disadvantages of the prior art compartmentalized truck and trailer arrangements.